This invention relates to water skis, and more particularly to a water ski having a floodable fluid chamber to permit change in the weight distribution when the water ski is in motion or stationary.
Conventional water skis are made of uniform, solid buoyant material, such as wood, fiberglass or other plastic compositions, with a weight distribution such that when the ski is stationary in the water, it floats flat on top of the water. When the ski is in skiing position moving forward through the water, it has the same weight distribution as it does when it is stationary, except that it asumes a planing attitude, with the forward end of the ski slightly raised.
However, when a skier attempts to place the skis on his feet in the water, the aft sections of the skis must be manually forced downward into the water so that the ski assume a substantially upright positions to permit the skier to insert his feet in the foot supports or foot harness on the respective skis. Sometimes it is difficult enough to insert each foot into a separate ski, much less maintain the buoyant aft section of the ski depressed under water while the foot is being inserted. After the skis have been assembled upon the feet of the skier, then the skier must still force the buoyant aft sections of the skis downward and simultaneously maintain the skis substantially parallel and upright until the skier is drawn forward by the ski rope pulled by the towing motor boat.
Furthermore, after a skier becomes separated from his skis, such as by falling or loss of control, sometimes, it is difficult for the skier to relocate the separated skis which are floating flat on top of the water, particularly where waves are present which conceal the skis from view of the skier whose eyes are substantially at water level.
Applicant is aware of only two instances of prior attempts to solve the above problems. One is the water ski disclosed in the U.S. Pat. No. 3,031,697 to Klein, in which the front or fore portion of the ski is made buoyant, while the aft or rear section of the ski is provided with a fixed lead weight in order to provide a permanent weight variation between the fore and aft sections of the ski. Although the Klein U.S. Pat. No. 3,031,697 provides a solution for maintaining the water ski in an upright position when it is in a relatively stationary position, nevertheless, the skier must contend with the same weight variation between the fore and aft sections when the skis are in their skiing position. In other words, the Klein water ski is provided with a permanent unbalanced weight distribution in the fore-aft direction, whether the ski is in motion or stationary.
The U.S. Wright U.S. Pat. No. 4,296,511 discloses a water ski having an elongated air chamber extending throughout the middle section of the ski with a large air inlet in the top of the fore section of the ski. The rear end portion of the air chamber has a discharge aperture 28 in the bottom surface of the ski communicating with the water supporting the ski. A transverse skag 11 is mounted on the ski beneath the discharge aperture 28 to create a Venturi effect beneath the bottom surface of the ski. Moreover, the passage of fluid, either water or air, through the discharge aperture 28 is controlled by a vane 32 journaled about a transverse axis and normally biased to an open position when the ski is in a substantially stationary position. In the stationary position, with the pivotal vane open, the air chamber 25 is flooded to cause the ski to attain an upright position. When the ski is in forward motion, the rearward movement of the water closes the pivotal vane 32 to close the air chamber 25. However, the vane is provided with a plurality of small nozzles 33 which will permit limited passage of first water, and then air, from the air chamber downward beneath the ski, as the ski moves forward through the water.
Since the air chamber 25 in the Wright U.S. Pat. No. 4,296,511 is disclosed in substantially the mid-section of the ski and there is a solid aft portion of the ski located behind the air chamber, then the solid aft portion must have a density greater than that of water in order to facilitate the downward movement of the aft section of the ski when the air chamber 25 is flooded. If this is true, then there will be a permanent imbalance between the fore and the aft densities of the ski, even when the water from the air chamber has been discharged during the forward skiing motion of the ski. Furthermore, it is noted in the Wright patent that the rearward movement of the water within the chamber 25 when the ski begins to plane, has to change direction from rearward to downward, as well as having to pass through the constricted nozzles 33.
Furthermore, it is noted in the Wright patent that the transverse strength of the ski is diminished across the rear portion of the air chamber 25 where the pivotal vane 32 is located, an area where the stress is substantially great.
Other skis having fluid passages are disclosed in the following U.S. Pat. Nos.
2,382,150, Hartman, Aug. 14, 1945 PA1 3,284,823, Steffel, Nov. 15, 1966 PA1 3,318,609, Ross, May 9, 1967 PA1 3,874,315, Wright, Apr. 1, 1975